New Search UI

Summary: This is the new search UI as seen in Pholio. Unrounds it (mostly, and makes the eyeglass more button like.

Test Plan:
Review in all header colors, check photoshop for pixel layout consistency. Review in FF, Chrome, Safari, IE. Make sure I didn't mess up mobile.

{F359366}

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12277